Infectious mononucleosis is characterised by the classic triad of fever, pharyngitis, and lymphadenopathy, along with atypical lymphocytosis. It is often subclinical in young children.
Caused by infection with Epstein-Barr virus (EBV) in 80% to 90% of cases. Positive heterophile antibody test and serological test for antibodies against EBV are usually diagnostic.
Rare but potentially life-threatening complications include severe upper airway obstruction, splenic rupture, fulminant hepatitis, encephalitis, severe thrombocytopaenia, and haemolytic anaemia.
Treatment is usually symptomatic.
Infectious mononucleosis (IM), also known as glandular fever, is a clinical syndrome most commonly caused by Epstein-Barr virus (EBV) infection in 80% to 90% of cases. Other causes are much less common. The diagnosis 'infectious mononucleosis' is primarily used when the syndrome is caused by EBV; 'mononucleosis syndrome' should be used when the syndrome is caused by a non-EBV aetiology. This topic focuses on IM caused by EBV.
IM typically manifests in adolescents and young adults as a febrile illness with sore throat and enlarged lymph nodes. Atypical lymphocytosis and a positive heterophile antibodies test are usually observed. The disease is generally mild in children, but more severe in adults. Resolution of the acute illness is usually followed by a lifelong latent infection, with over 90% of the adult population infected worldwide.
History and exam
Key diagnostic factors
- presence of risk factors
- cervical or generalised lymphadenopathy
Other diagnostic factors
- signs of hepatitis (hepatomegaly, jaundice)
- sexual behaviour
1st investigations to order
- heterophile antibodies
- Epstein-Barr virus (EBV)-specific antibodies
Investigations to consider
- real-time polymerase chain reaction (PCR)
- ultrasonography of abdomen
- CT of abdomen
George Turabelidze, MD, PhD
Missouri Department of Health and Senior Services
Adjunct Assistant Professor of Clinical Pediatrics
Washington University School of Medicine
GT declares that he has no competing interests.
Linda Kalilani, MBBS, MPhil, PhD
College of Medicine
University of Malawi
LK declares that she has no competing interests.
Paul G. Auwaerter, MD, MBA, FACP, FIDSA
Division of Infectious Diseases
Associate Professor of Medicine
Divisions of Infectious Diseases and General Internal Medicine
Johns Hopkins University School of Medicine
PGA declares that he has no competing interests.
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